Through annual medical history, dermatologic, ophthalmic and laboratory examinations, and dosimetry data, the Photochemotherapy Cooperative Follow-Up Study will determine the clinical efficacy and safety of photochemotherapy prior to Setptember, 1976. These individuals will be followed for a five-year period. The follow-up examinations will establish the incidence of potential major and minor toxicities or side effects of photochemotherapy. In addition, the study will assess patient acceptability and factors affecting clinical efficacy.